Millions of Americans are infected by the hepatitis B virus (HBV). Many of those victims have no reason to believe they are infected. There is a need to track down America's millions of HBV victims-as well as a corresponding need for innovative technology to test blood for HBV. HBV is clearly a national medical priority. The overall goal of this project is to further develop and then integrate core sensor and enzyme immunoassay technologies into a novel technique for the rapid and accurate measurement of HBV levels in blood. We are targeting diagnostic (detection) applications as well as quantitative measurement needs (to monitor viral levels and treatment efficacy). The specific Phase I goal is to demonstrate the feasibility of integrating a unique electrochemical measurement method with proprietary electrochemical enzyme immunoassay architecture to produce a new diagnostic/monitoring capability for "real time," cost- effective HBV assessment in an outpatient setting. The product we envision is a disposable HBV test strip that can be read by an inexpensive, small (hand-held) instrument. It would represent a key development in medical diagnostics that would address major domestic and international market needs for low-cost HBV screening and monitoring. PROPOSED COMMERCIAL APPLICATIONS: The health care market has a major need for a diagnostic device that can screen in "real time" for hepatitis B virus (HBV) in patient blood and can also quantitatively monitor the blood for therapeutic response. Such a device would assist health care providers in identifying and treating the numerous undiagnosed cases of HBV infection. The same device would service patients in various settings, such as bedside, emergency room, clinic, and home.